OBJECTIVES: The goals of this project are: a) Investigation of the development of serum nuclease isoenzymes related to cancer, in particular, 5'-nucleotide phosphodiesterase; b) Evaluate the newly developed 5'-nucleotide phosphodiesterase isoenzyme test for both malignant and non-malignant hepatic disease; c) Prospective study of this new test as an early marker for hepatic metastases; d) Possible use of this marker for active hepatitis B, late cirrhosis, and active non-hepatitis B donors in blood transfusion; e) Provides methods for localization of izoenzymes of 5'-nucleotide phosphodiesterase in tissue; and f) Study the physiology of the development of this enzyme. METHODS: Gel electrophoresis of sera of cancer patients, quantitation by gel scanning, and development of alternate immune assay. Comparison of other liver function tests, liver scan and other marker proteins will be done in this project. Isoelectric focusing will be used as improved resolution for the isoenzymes for differential diagnosis. Animal model study will be carried out in mouse hepatoma. Immunohistochemical and cytochemical studies of tissue will be made, using anti-enzyme anti-sera prepared from purified isoenzymes.